DIY: Circle of Confusion Shape Modifier

We are always happy to get a nice bokeh build tutorial in the blog, even if it means we have to throw away the name of our best product and find it a new one, maybe the circle of confusion masters kit

Circle of Confusion Shape Modifier – At least that’s what I call it. I call it that because “circle of confusionrefers to the actual defocused spot, while “bokehrefers to the aesthetic quality of the blurring caused by the larger-than-a-point circles of confusion. If you disagree with my reasoning, just ignore the title (darn, need to think of a new product name, UT). Anyway, since you are reading this, you have probably seen this article. I really liked the idea and made one just like it. It worked very well, but to make one for every shape I might want seemed a bit impractical due to the amount of space such a collection would require. So I set out to solve that “problem.” And here is what I came up with…

DIY: Circle of Confusion Shape Modifier

As you can (hopefully) see above, the hood consists of four basic parts—the round part that wraps around the lens; a front part with a large cutout; a slot, into which you slide the, er, slides; and a little part at the top that helps to line up the slide and keep it secure when upside-down. Note that yours will look a little different than mine. I designed the slot after cutting out the rest of the hood, so mine is a bit rough.

What you’ll need to make one:

  • One large aperture lens (I used a Canon 50mm f/1.8 II)
  • Black cardstock (I found 50 sheets at a local craft store for $4, or $2.80 with a coupon:)
  • Photoshop or Photoshop Elements or Gimp (I used Pse7)
  • An X-Acto knife (or similar) with a nice, sharp blade
  • A cutting mat (…like this one. It’s not required, but I highly recommend using one.)
  • White Elmer’s glue or a glue stick
  • Tape

Follow those steps

To make your own, start by opening up Photoshop. Create a new 8.5×11” image. Now, go to View>Grid and make sure it’s checked. The grid will help A LOT in getting things lined up. You’ll notice how some of the lines are darker. Pick one of the dark crosses toward the middle and zoom to 300+%. Use the custom shape tool to create the following image. Line up the cursor with a dark cross when you create a shape. This may sound a bit overkill, but it ensures that everything is lined up properly.

DIY: Circle of Confusion Shape Modifier


  • outer circle= 70x70mm
  • lines= 110x5mm, 5x110mm
  • square= 45x45mm
  • inner circle= 35x35mm

*These dimensions work for the 50/1.8. You may need to modify them if your lens has a different diameter.

Save the file, and create a new 8.5×11” image. Zoom in to 300+% again and start creating 45x45mm squares at the dark crosses. I fit 12 of them arranged like this:

DIY: Circle of Confusion Shape Modifier

Obviously, I could have fit more squares on the page, but I didn’t want to risk having my printer not print some of the sides. Once you have made the squares, set the custom shape tool’s size to 15x15mm (I used 15 because I knew it would work, but you can experiment with other sizes if you want) and start adding some shapes. With some of the shapes, you will have to reduce one of the dimensions. Just try different numbers until it looks right.

You can also draw your own shapes if you want, but be careful not to make them too big. When you’re done, save this file, too.

Now it’s time to print and do some cutting. If you have a cutting mat, use it. It will make the entire cutting process much easier. You can use cardboard in a pinch, though. All of the areas below that are red need to go.

DIY: Circle of Confusion Shape Modifier

The two lower cutouts (2 & 3) form the slot. The height doesn’t have to be exact, just reasonably close. The point is that part 3 is taller than part 2. Glue part 2 onto part 1, then part 3 onto part 2. Glue part 4 onto part 1, across from the slot. You also need to cut a 1-1.25” strip from the long side of a sheet of cardstock. Wrap it tightly around your lens. Tape it and glue down the flap you just created. From here the construction should be obvious.

The page with the slides should be self-explanatory.

To store all of those slides, I used an “ancient” case designed for a Game Boy cartridge. If you don’t have one of those, one of these would work just as well. …Or, get creative and make something. :) The hood can be stored in the cardboard lens box when traveling so it isn’t crushed.

And you’re done! Enjoy! Let me know in the comments section how you like it.

DIY: Circle of Confusion Shape Modifier

DIY: Circle of Confusion Shape Modifier

50mm 1.8 Lenses [B&H | Amazon]

50mm 1.8 LensesThe 50mm 1.8 is probably the best value for money any you’ll find. They are sharp, fast and compared to other fast glass darn cheap. 50mm lenses give a really nice bokeh which is the reason they work so well for shaped bokeh shots.

Bokeh Masters Kit [DIYP | Amazon | B&H]

The Bokeh Masters KitThe bokeh masters kit turns light into shapes. If you are not that handy with an utility knife or simply don’t have the time to make the device above, you can always got one of our fabulous kits. They come with a lens adapter, 21 pre-cut shapes and 8 blank discs just in case you change your mind about the knife.

Article and images by Mike Gerdau.

  • Uyen Nguyen

    what’s the point of cluing part 4 onto part 1? I think part 2 & 3 are enough for the card to be held, aren’t they?